How can we use this app?

Dear sir,
How can we use this app?
Do we need to add some codes?
Now we are using product reviews app from shopify.How can we change this to your app and what will happen to the exist reviews?
Look forward to hearing from you.
Best regards.

How can we use this app?
For use this apps you need put code on product liquid file how to do this it will me on Help & Support tab and help/install menu of sidebar click on this and follow the step give in to this